Virtual destructors should have virtual keyword.

media/base/filters.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Filters are connected in a strongly typed manner, with downstream filters
 // always reading data from upstream filters.  Upstream filters have no clue
 // who is actually reading from them, and return the results via callbacks.
 //
 //                         DemuxerStream(Video) <- VideoDecoder <- VideoRenderer
 // DataSource <- Demuxer <
@@ skipping 249 matching lines @@
 
   // Installs a permanent callback for passing decoded audio output.
   typedef base::Callback<void(scoped_refptr<Buffer>)> ConsumeAudioSamplesCB;
   void set_consume_audio_samples_callback(
       const ConsumeAudioSamplesCB& callback) {
     consume_audio_samples_callback_ = callback;
   }
 
  protected:
   AudioDecoder();
-  ~AudioDecoder();
+  virtual ~AudioDecoder();
 
   // Executes the permanent callback to pass off decoded audio.
   void ConsumeAudioSamples(scoped_refptr<Buffer> buffer);
 
  private:
   ConsumeAudioSamplesCB consume_audio_samples_callback_;
 };
 
 
 class VideoRenderer : public Filter {
@@ skipping 19 matching lines @@
   // buffer.
   virtual bool HasEnded() = 0;
 
   // Sets the output volume.
   virtual void SetVolume(float volume) = 0;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_FILTERS_H_